Total protein determination before Elisa?

Is total proten determination usefull before an Elisa assay.
I want to measure a protein in Bronchoalveolara Lavage Fluid (BALf) which is the lining fluid from the bronchial and alveolar epithelium. It is aspirated with saline through Bronchoscope

What is the point of measuring the total protein concentration??
The most papers i have reviewed, using Elisa in BALf, have results in pg/ml or ng/ml or ug/ml and they have not performed an assay for the total protein concentration.

We often use total protein with ELISA to normalize data between samples taken from different sources. If some samples have more total protein, they may contain more of the protein of interest which can lead to incorrect conclusions. It really depends on what the experiement is and what your source of sample is. If you are following a classical method for analysis that is accepted in the literature for the work you are doing, then that sounds like what you should do. I'm not familiar with your experiment but can offer this explanation for why I use the two measurements.